Sulphonation of organic compounds



g- 1966 P. MARSHALL ETAL 3,270,033

SULPHONATION OF ORGANIC COMPOUNDS Filed May 24, 1962 INVENTORS ATTORNEY United States Patent 3,270,038 SULPHONATION OF ORGANIC COMPOUNDS Philip Marshall, Timperley, and John M. Blakeway, Bowdon, England, assignors to Colgate-Palmolive Company, a corporation of Delaware Filed May 24, 1962, Ser. No. 197,508 Claims priority, application Great Britain, May 26, 1961, 19,157 61 10 Claims. (Cl. 260400) This invention relates to the sulfonation of organic compounds with sulfur trioxide. The term sulfonation is used herein to include both true sulfonation and sulfation, in accordance with common usage in the detergent art.

It is an object of the invention to provide a process and apparatus which permit sulfonation of organic compounds to produce good yields of high quality sulfonated products.

According to one aspect of the invention, there is provided a process for sulfonating an organic compound which comprises flowing said compound to be sulfonated in liquid phase as a free annular jet from a zone of relatively high pressure to a zone of relatively low pressure to set up a zone of turbulence in said liquid, introducing into the centre of said jet a gaseous mixture of sulfur trioxide and inert gas to react with the organic compound and obtaining a sulfonated organic compound.

The transition from said zone of relatively high pressure to said zone of relatively low pressure may be effected by an annular orifice, the flowing of said organic compound through said orifice setting up said zone of turbulence downstream of the orifice.

According to another aspect of the invention, there is provided apparatus for carrying out the sulfonation of an organic compound which comprises a first conduit, 9. plate having an orifice therein dividing said conduit into a zone of relatively high pressure and a zone of relatively low pressure, a nozzle protruding through said orifice from the zone of relatively high pressure to the zone of relatively low pressure, means for flowing said organic compound in liquid phase through said conduit from the zone of relatively high pressure into the zone of relatively low pressure and means for feeding a gaseous mixture of sulfur trioxide and an inert gas through said nozzle into said zone of relatively low pressure.

The expression organic compound in liquid phase is intended to embrace not only organic compounds which are true liquids under the reaction conditions, but also solutions, suspensions and slurries of organic compounds which are essentially liquid in character under the reaction conditions.

Any organic compound capable of being sulfonated by sulfur trioxide in liquid phase as above defined can be subjected to the process and employed in the apparatus. Among such organic compounds are aliphatic saturated alcohols, polyhydric alcohols, saturated fatty acids, aliphatic olefins, aromatic hydrocarbons, alkylated aromatic hydrocarbons, aromatic polycyclic hydrocarbons and fatty acid alkanolamides. Of particular importance among the organic compounds which can be sulfonated by the process or in the apparatus are the alkyl benzenes, especiallly those containing 9 to 20 carbon atoms in the alkyl group, fatty alcohols containing 5 to 20 carbon atoms, and ethylene oxide or propylene oxide condensation products obtained by condensing from 1 to moles of ethylene oxide or propylene oxide with a mole of a compound such as an alkyl phenol containing from 8 to 20 carbon atoms in the alkyl group, or a fatty alcohol or acid containing from 9 to 20 carbon atoms, or a fatty acid alkanolamide containing from. 9 to 20 carbon atoms in the fatty acid residue and from 2 to 4 carbon atoms in the alkanol group. Mixtures of any two or more of the above compounds are also suitable.

The sulfur trioxide used as the sulfonating agent can be obtained from various sources. For example, it may be obtained by vaporizing liquid sulfur trioxide, from oleum or from other sources. The inert gas used to dilute the sulfur trioxide can be air, hydrogen, nitrogen, sulfur dioxide, carbon dioxide or any other gas which is inert in the reaction medium or compatible mixtures thereof. The term inert as applied to the gas means that it will not react with sulfur trioxide, the organic compound or the sulfonate. It may react with by-products. For example, hydrogen may have a reducing effect upon certain undesirable by-products which may tend to discolor the sulfonate.

'In carrying out the process the reactants can be utilised in widely varying amounts. However, in order to obtain good yields of high quality sulfonated product, it is preferred that the sulfur trioxide be employed in a molar ratio of 0.8 to 2.0 per mole equivalent of organic compound. Furthermore, the sulfur trioxide concentration in the inert gas may be from about 0.5% to 50.0%, and preferably from 5.0% to 20.0%, by volume, based on the volume of the gasous mixture and calculated at 15 p.s.i. absolute and room temperature. In the zone of turbulence the ratio of gaseous mixture and organic compound is preferably in the range 0.5 :1 to 20:1 by volume. Although these limits are not critical, best results are achieved when the process is carried out within them.

The temperature of the reaction between the sulfur trioxide and organic compound can also vary within wide limits. Since the reaction is exothermic, care should be taken to prevent charring which will adversely affect color. The temperature should not exceed about C. The reactants may be introduced into the passages at room temperature, unless the organic compound is not in liquid phase at this temperature. When the organic compound is a solid at room temperature, it may be melted by a preheating arrangement and fed into the first pass-age at elevated temperature to keep it in liquid form, or it may be dissolved or dispersed in a liquid solvent or carrier.

In one form of the invention at least a portion of the reaction product is returned to the zone of relatively high pressure for recycling, in order to improve the overall yield. It is desirable to cool the reaction products being returned in order to prevent a progressive increase in the reaction temperature. I

Where reaction product is recycled, it may be mixed with inert gas, e.g. dry air or nitrogen, for example by injecting air into the reaction product return line. The bubbles of inert gas in the liquid expand as the pressure drops when it enters the zone of relatively low pressure and increase the turbulence.

Turbulence can also be increased by providing a sharp edged orifice.

The invention may be performed in various ways, and a specific embodiment will now he described by way of example with reference to the accompanying diagrammatic drawing, which shows one form of apparatus acexample with reference to the accompanying diagrambeing in section and on a larger scale than the lower part.

The apparatus illustrated comprises a reactor consisting of a first passage 11 having an orifice plate :12 dividing it into a zone 13 of relatively high pressure and 'a zone 14 of relatively low pressure. A second passage 15 is connected to a source of sulfur trioxide and inert gas and terminates in a nozzle 16 protruding slightly beyond the :orifice 17 in the plate -12. Owing to the presence of the nozzle 16 .the orifice 17 is annular, and it is sharp edged to promote turbulence. A conduit 18 feeds organic compound to the zone 13 of relatively high pressure. A flow breaker 19 is disposed in the zone 14 of relatively low pres-sure, at a distance from the orifice plate 12, while a further flow breaker 20 is disposed in the conduit 18 just upstream of its junction with the first passage 11. The flow breakers may be in a variety of forms and may consist of a variety of materials. Interlinked open helical coils of wire of a metal that is not attacked by sulfur trioxide are suitable. The purpose of the flow breaker 19 is to extend the zone of turbulence of the liquid organic compound which emerges as a free annular jet from the orifice 17. The purpose of the flow breaker 19 will be explained below.

A holding tank 21 contains vaporized sulfur trioxide from a source such as those indicated hereinabove. A stream of inert gas, that is dry air, is tapped ofi from an air supply line 26 through a line 22 and is delivered to the tank 21 where it entrains sulfur trioxide vapor, the mixture passing into the second passage 15 where it mixes with a further quantity of air which enters via a valve '32 from the supply line 26.

The gaseous mixture of sulfur trioxide and inert gas then passes into the low pressure zone 14 of the reactor from the passage 15 through the nozzle 16.

A holding tank 23 contains the sulfonatable organic compound which is pumped in liquid phase by a pump 30 to the high pressure zone 13 of the reactor by way of the conduit 18. From the high pressure zone 13, the organic compound passes through the annular orifice 17 as a free annular jet into the low pressure zone 14 with a considerable drop in pressure, thereby creating a zone of turbulence in the organic compound on the low pressure side of the reactor which results in uniform mixing of the sulfur trioxide/ air mixture with the organic compound. The sharp edge of the orifice 17 enhances the turbulence and the flow breaker 19 extends the zone of turbulence, as already mentioned. The cross-section of the turbulent zone is increased towards the outlet end thereof to help diminish the rate of linear flow of the reactants, to provide time for the reaction to be substantially completed in the turbulent zone.

Additional air, or other inert gas, can be introduced into the organic compound in the conduit 18 by way of a conduit 24. Such introduction of inert gas is optional. However, when employed, it can be used in amounts of up to 100% by volume (calculated at the pressure and temperature of the liquid), based on the volume of liquid being supplied to the reactor through the conduit 18. When such inert gas introduction is employed, the flow breaker 20 serves to break up the gas into small bubbles. As these bubbles pass through the orifice 17 they expand and increase the turbulence. The reaction products pass from the low pressure zone 14 of the reactor directly into a collection vessel 25. A venting line 27 for exhaust gases is provided on the collection vessel. A recycling or return line 28 connects the collection vessel to the conduit 18 so that at least a portion of the reaction products can be returned by the pump 30 to the high pressure zone 13 of the reactor after pass ing through a cooling heat exchanger 31. A take-off conduit 29 permits removal of the product from the system at will. When operating with a high degree of recycling the reaction temperature can in some cases be controlled wholly by means of the cooling effected in the heat exchanger 31. In other cases, where further cooling is required, this can be efiected in any convenient way, for example by enclosing the reactor in a cooling jacket.

The process can -be performed as, and .the apparatus can be employed for, a continuous or batch production process.

If a relatively low degree of sulfonation is sufiicient there is no need to recycle any of the product.

For efiicient operation, pressures in a range of 10 p.s.i. abs. to 300 p.s.i.g. are preferred in the zone 13 of relatively high pressure and pressures in a range of about p.s.i. abs. to p.s.i.g. are preferred in the zone 14 of relatively low pressure. The pressure drop across the orifice 17 is in a range of 5 to 300 p.s.i.g. The pressure drop should of course be sufficient to provide the required degree of turbulence under the prevailing operating conditions. The gaseous mixture of sulfur trioxide and inert gas is delivered to the low pressure zone 13 at a velocity in the nozzle 16 in a range of 50 ft./sec. to sonic velocity. The organic liquid is fed through the annular orifice 17 to the low pressure zone 14 at a velocity in a range of 5 ft./sec. to 500 ft./sec. Although such pressures and velocities are not critical, pressures and velocities can be selected within the ranges set forth to create a zone of turbulence sufiiciently strong to result in uniform mixing of the sulfur trioxide and sulfonatable stantially complete.

When employing the process and apparatus in a continuous manner, a liquid stream of sulfonatable organic compound is fed to the reactor and passes through it to the collection vessel 25. Concurrently, the gaseous mixture of sulfur trioxide and inert gas is led to the low pressure zone 14 of the reactor and contacts the organic compound in a zone of turbulence which has been established on passage of the compound through the annular orifice 17 from the high pressure zone 13 to the low pressure zone 14. After collection in the vessel 25, at least a portion of the product, and any unreacted organic compound it may contain, is returned to the zone 13 of high pressure by way of the line 28 from which it is pumped to the conduit 18 and is mixed with organic compound from the tank 23 before return to the reaction Accordingly, a stream of product and organic compound is continuously being supplied to the high pressure zone of the reactor. While recycling is in progress, product is also being continuously withdrawn through the take-off line 29.

: ent in the holding tank 21 can be adjusted so that there is very little more than the amount required for the desired degree of sulfonation of' the organic material. In such a case it is preferred not to draw off any product from the collecting vessel 25 via the line 29 until all the sulfur trioxide has been absorbed. In a batch process it is convenient to have duplicate collecting vessels, one receiving product while the other is being emptied and prepared for the next batch.

The following examples further illustrate the invention. In the examples all parts and percents are by weight unless otherwise stated.

EXAMPLE I Batchwise sulfonation of tetrapropylene benzene A mixture of 85.6% by volume of dry air and 14.4% by volume of sulfur trioxide vapor produced from stabilized liquid sulfur trioxide was passed through the nozzle 16 (internal diameter 0.078") of the reactor at 18 p.s.i.g. where it was intimately mixed with 2628 grams of re cycled tetrapropylene benzene over a period of 25 minutes. Air in an amount of 30% by volume (measured at atmospheric pressure) of the recycled liquid was injected into the liquid stream at 24, upstream of the flowbreaker 20. The pressure drop across the annular orifice 17 (inside diameter 0.125, outside diameter 0.204) increased from 19 p.s.i.g. to 182 p.s.i.g. as sulfonation proceeded to completion. The molar ratio of sulfur trioxide to tetrapropylene benzene was 1.05:1. The temperature in the reaction zone was maintained at about 54 C.

Analysis of product: Percent Tetrapropylene benzene sulfonic acid 97.8. Free oil 1.3. Inorganic acid 0.9. Color of sodium salt 112 Klett.

(Color determined on a 5% solution of the sodium salt of the sulfonic acid read in a 40 mm. cell of a Klett- Summerson photoelectric colorimeter using a No. 42 blue filter.)

EXAMPLE II Batchwise sulfonation of tetrapropylene benzene A mixture of 87.90% by volume of dry air and 12.10% by volume of sulfur trioxide vapor produced from stabilised liquid sulfur trioxide was passed through the nozzle 16 (internal diameter 0.547") of the reactor at a pressure ranging from 11 to 14 p.s.i.g. Where it was intimately mixed with 400 pounds of recycled tetrapropy-lene benzene in liquid phase over a period of 1 hour 35 minutes. The total amount of sulfur trioxide added was 138.5 pounds. The molar ratio of sulfur trioxide to tetrapropylene benzene was 1.065 :1. The liquid tetrapropylene benzene passing through the annular orifice 17 was introduced at a pressure ranging from 45 to 55 p.s.i.g. The dimensions of the orifice 17 were: inside diameter 0.688" outside diameter 1.0". The temperature in the reaction zone was maintained at about 53 C.

Analysis of product: Percent Tetrapropylene benzene sulfonic acid 97.4. Free oil 1.5. Inorganic acid 1.1. Color of sodium salt 202 Klett.

(Color determined as in Example I).

EXAMPLE III Continuous sulfonation of tetrapropylene benzene A mixture of 88.2% by volume of dry air and 11.8% by volume of sulfur trioxide vapor produced from stabilized liquid sulfur trioxide was passed through the nozzle 16 (dimensions as in Example 1) into 1275 gms. of recycled reaction mixture at a pressure of 17 p.s.i.g. Simultaneously and continuously, tetrapropylene benzene was being added to the system via tank 23 at a rate of 67.5 grams/minute, and product was being taken out of the system continuously via 29 at a rate such that the level in tank 25 was kept constant. The pressure drop across the orifice was 110 p.s.i.g. and the reaction was held at a temperature of 55 C. The gas-liquid ratio through the low pressure zone was 2.67: 1.

The sulfonic acid extracted from the apparatus continuously had a free oil content of 1.0%, and the color of the sodium salt (measured in the same manner as in the previous examples) was 375 Klett.

EXAMPLE IV Batchwise sulfonation (sulfation) of thylene oxide adduct of fatty alcohols 91.5% by volume of dry air and 8.5% by volume of sulfur trioxide vapor produced from stabilized liquid sulfur trioxide was passed through the nozzle 16 (dimensions as in Example I) of the reactor where it was intimately mixed with a mixture of:

Percent Cetyl/oleyl alcohol 25 Cetyl/oleyl alcohol ethylene oxide adduct (4 moles of ethylene oxide per mole of fatty alcohols) 29 Lauryl alcohol 46 The total reaction time was 88 minutes and the tempertaure in the reaction zone was maintained between 50 C. and 55 C.

The acid .so formed was neutralized with caustic soda and the sodium salt had the composition:

Percent Alkyl and alkyl ether sulfates 65.9 Sodium sulfate 0.6 Unchanged non-ionics 3.3

Water 30.1

The color of the paste (measured as described in pr vious examples) was 250 Klett.

EXAMPLE V Batchwise sulfonation (sulfation) of ethylene oxide adduct of tridecyl alcohol 89.1% by volume of dry air and 10.9% by volume of sulfur trioxide vapor produced from stabilized liquid sulfur trioxide was passed through the nozzle 16 (dimensions as in Example II) of the reactor where it was intimately mixed with 287 pounds of ethylene oxide adduct of tridecyl alcohol (3 moles ethylene oxide per mole of alcohol).

The total reaction time was 77 minutes and the temperature in the reaction zone was maintained below 43 C.

The acid so formed was neutralized with caustic soda and the sodium salt had the composition:

Percent Tridecyl ether sulfate 29.6 Sodium sulfate 1.4 Unchanged non-ionic 0.9 Water 68.1 The color of the paste was light brown.

EXAMPLE VI Batchwise co-sulfonation of alkylate and xylene 86.4% by volume of dry air and 13.6% by volume of sulfur trioxide vapor produced from stabilized liquid sulfur trioxide was passed through the nozzle 16 (dimensions as in Example I) of the reactor where it was intimately mixed with a mixture consisting of 2610 gm. of alkylate (alkyl aryl hydrocarbon) and 401 gm. of xylene.

The total reaction time was 43 minutes and the temperature in the reaction zone was maintained below 50 C.

The product so formed had the composition:

Percent Alkyl aryl sulfonic acid 83.7 Xylene sulfonic acid 13.3 Free oil 2.7 Sulfuric acid 0.3

Neutralization with caustic soda gave a product having a color of 164 Klett, measured in the same manner as in Example I.

What we claim as our invention and desire to secure by Letters Patent is:

1. A process for sulfonating a sulfonatable organic compound selected from the group consisting of alcohols, fatty acids, olefins, aromatic hydrocarbons, alkylated aromatic hydrocarbons, fatty acid alkanolamides, ethoxylated alkyl phenols, ethoxylated fatty alcohols, ethoxylated fatty acids and ethoxylated fatty acid alkanolamides, with a gaseous mixture of sulfur trioxide and an inert gas which comprises flowing said sulfonatable compound in the liquid phase in a zone of relatively high pressure in a range of 10 p.s.i. absolute to 300 p.s.i.g. restricting the flow of said liquid phase and sufficient to form a free annular jet of said sulfonatable liquid at a velocity in a range of 5 feet per second to 500 feet per second in a zone of relatively low pressure in a range of about 5 psi. absolute to 10 p.s.i.g. and suflicient to create a zone of turbulence in said liquid, injecting a gaseous mixture of sulfur trioxide and inert gas into the center of said free annular jet in said low pressure zone at a velocity in the range of 50 feet per second to sonic velocity and sufiicient to result in uniform mixing of said sulfur trioxide and sulfonatable organic compound in the zone of turbulence, and maintaining said uniform mixture of sulfur trioxide and sulfonatable material in said low pressure zone until absorption of the sulfur trioxide is substantially complete.

2. A process according to claim 1 in which the rate of linear flow of the reacting mixture of organic compound and sulfur trioxide is diminished to provide a time factor for substantially completing the reaction.

3. A process according to claim 1 in which said organic compound is selected from the group consisting of alkylbenzenes, fatty alcohols and ethylene oxide adducts of a material selected from the group consisting of alkyl phenols, fatty alcohols, fatty acids and fatty acid alkanolamides.

4. A process according to claim 1 in which said inert gas is selected from the group consisting of air and nitrogen.

5. A process according to claim 1 in which the sulfur trioxide is employed in an amount of 0.5% to 50.0% by volume, based on the volume of the inert gas.

6. A process according to claim 1 in which the weight ratio of said gaseous mixture and said organic compound is 0.5:1 to 20:1.

7. A process according to claim 1 in which the reaction temperature is in a range of C. to 80 C.

8. A process according to claim 1 in which the pressure drop from said zone of relatively high pressure to said zone relatively low pressure is in a range of 5 to 300 p.s.i.g.

9. A process according to claim 1 in which at least a portion of said sulfonated organic compound is recycled to said zone of relatively high pressure.

10. A process for sulfonating a sulfonatable organic compound selected from the group consisting of alcohols, fatty acids, olefins, aromatic hydrocarbons, alkylated aromatic hydrocarbons, fatty acid alkanolamides, ethoxylated alkyl phenols, ethoxylated fatty alcohols, ethoxylated fatty acids and ethoxylated fatty acid alkanolamides, with a gaseous mixture of sulfur trioxide and an inert gas comprising flowing said compound to be sulfonated in liquid phase as a free annular jet through an annular orifice from a zone of relatively high pressure to a zone of relatively low pressure to set up a zone of turbulence in said liquid and introducing into the centre of said jet a gaseous mixture of sulfur troxide and inert gas to react with said organic compound and form a sulfonated organic compound.

References Cited by the Examiner UNITED STATES PATENTS 2,174,760 10/1930 Schuette et a1 260-400 2,290,167 7/1942 Datin 260-400 2,371,284 3/1945 Cook et al. 260-400 2,634,287 4/1953 Fincke et al. 260459 2,665,197 1/1954 Rowland 23285 2,730,433 1/1956 Cartledge 23285 2,828,331 3/1958 Marisic et al. 260400 2,865,958 12/1958 Davis et al 260400 2,872,297 2/1959 Dugan 23285 2,923,728 2/1960 Falk 260459 FOREIGN PATENTS 27,274 7/ 1932 Netherlands.

CHARLES B. PARKER, Primary Examiner.

DANIEL D. HORWITZ, Examiner.

FLOYD HIGEL, Assistant Examiner. 

1. A PROCESS FOR SULFONATING A SULFONATABLE ORGANIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF ALCOHOLS, FATTY ACIDS, OLEFINS, AROMATIC HYDROCARBONS, ALKYLATED AROMATIC HYDROCARBONS, FATTY ACID ALKANOLAMIDES, ETHOXYLATED ALKYL PHENOLS, ETHOXYLATED FATTY ALOCHOLS, ETHOXYLATED FATTY ACIDS AND ETHOXYLATED FATTY ACID ALKANOLAMIDES, WITH A GASEOUS MIXTURE OF SULFUR TRIOXIDE AND AN INERT GAS WHICH COMPRISES FLOWING SAID SULFONATABLE COMPOUND IN THE LIQUID PHASE IN A ZONE OF RELATIVELY HIGH PRESSURE IN A RANGE OF 10 P.S.I. ABSOLUTE TO 300 P.S.I.G. RESTRICTING THE FLOW OF SAID LIQUID PHASE AND SUFFICIENT TO FORM A FREE ANNULAR JET OF SAID SULFONATABLE LIQUID AT A VELOCITY IN A RANGE OF 5 FEET PER SECOND TO 500 FEET PER SECOND IN A ZONE OF RELATIVELY LOW PRESSURE IN A RANGE OF ABOUT 5 P.S.I. ABSOLUTE TO 10 P.S.I.G. AND SUFFICIENT TO CREATE A ZONE OF TURBULENCE IN SAID LIQUID, INJECTING A GASEOUS MIXTURE OF SULFUR TRIOXIDE AND INERT GAS INTO THE CENTER OF SAID FREE ANNULAR JET IN SAID LOW PRESSURE ZONE AT A VELOCITY IN THE RANGE OF 50 FEET PER SECOND TO SONIC VELOCITY AND SUFFICIENT TO RESULT IN UNIFORM MIXING OF SAID SULFUR TRIOXIDE AND SULFONATABLE ORGANIC COMPOUND IN THE ZONE OF TURBULENCE, AND MAINTAINING SAID UNIFORM MIXTURE OF SULFUR TRIOXIDE AND SULFONATABLE MATERIAL IN SAID LOW PRESSURE ZONE UNTIL ABSORPTION OF THE SULFUR TRIOXIDE IS SUBSTANTIALLY COMPLETE. 